Add a test for a script inside an HTML block

tests/testsuite/rendering/html_blocks/expected/script-in-block.html

@@ -0,0 +1,7 @@
+<div>
+    HTML block start
+<script>
+    // script stuff <here>
+</script>
+    < still in block
+</div>

tests/testsuite/rendering/html_blocks/src/SUMMARY.md

@@ -1,3 +1,4 @@
 # Summary
 
 - [Comment in list](./comment-in-list.md)
+- [Script in block](./script-in-block.md)

tests/testsuite/rendering/html_blocks/src/script-in-block.md

@@ -0,0 +1,7 @@
+<div>
+    HTML block start
+<script>
+    // script stuff <here>
+</script>
+    &lt; still in block
+</div>